By Sam Shikora (Political Editor). In 632 A.D., the Muslim prophet Mohammed died. Ever since his death, a rift has existed between Muslims who believe that Mohammed’s successor should have been his close friend, Abu Bakr, and those who believe that his successor should have been Ali, a family member of Mohammed. These groups are known as Sunni and Shia Muslims, respectively. Sunnis and Shiites are Islam’s two largest denominations.